Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics.Y1_Imported > 22 - Electric Fields > Flashcards

22 - Electric Fields Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

Define electric field strength at a point in space.

A

The force experienced per unit positive charge at that point.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is an electric field caused by?

A

Charged objects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What sort of objects experience force in an electric field?

A

Charged objects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Is electric field strength a vector?

A

YES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the direction of an electric field?

A

The direction that a positive charge would move when placed in the field.

POSITIVE TO NEGATIVE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the arrow on an electric field line represent?

A

The direction of the electric field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are electric field lines always perpendicular to?

A

The surface of a conductor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is the strength of an electric field represented by field lines?

A

Their density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is Coulomb’s Law?

In words

A

Any two point charges exert an electrostatic force on each other that is directly proportional to the product of their charges and inversely proportional to the square of the distances between them.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What equation defines Coulomb’s law?

A

F = kQq / r²

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is ε₀?

A

The permitivity of free space?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do we treat a uniformly charged sphere as?

A

A point charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do we calculate the electric field strength of a point charge using Coulomb’s law?

A

E = kQ / r²

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the electric field strength of a point charge NOT depend on?

A

The charge of the point charge in the field.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the main difference between electric and gravitational fields?

A

Gravitational fields are always attractive whereas electric fields can be either attractive or repulsive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What sort of field does a point charge produce?

A

A radial field.

17
Q

What is the equation for electric field strength between two parallel plates?

A

E = V / d

18
Q

What are the two units for electric field strength?

A

NC⁻¹

Vm⁻¹

19
Q

What two factors does the capacitance of a parallel plate capacitor depend on?

A

The surface area of the plates, A
The distance between the plates, d

C ∝ A / d

20
Q

What is the constant of proportionality in the relationship, C ∝ A / d?

A

ε₀ (For air)

21
Q

What do we use instead of the permitivity of free space when a dielectric other than air is used in a parallel plate capacitor?

A

ε

ε = ε₀ε₁ (Where ε₁ is the permitivity of the dielectric)

22
Q

How would you suspend a droplet of a charged liquid in an electric field?

A

Make the force of the electric field equal to the weight of the droplet.

23
Q

If an object between two parallel plates experiences a constant force due to the electric field, describe its acceleration?

A

Constant as well

24
Q

What must we do when calculating anything from a particle travelling HORIZONTALLY in a uniform electric field?

A

Consider its vertical and horizontal components separately.

25
Q

How do charges store energy?

A

Two like charges repel each other.

By forcing them together we are storing potential energy as we need to do work.

This energy is released when we release the charges.

26
Q

Where is the energy represented on a force distance diagram?

A

The area under the curve

27
Q

How do we calculate the work done on a charge?

A

W = Fx

28
Q

Define electric potential energy at a point

A

The work done per unit charge in bringing a point charge from infinity to that point.

29
Q

Why does the equation for electric potential energy only have a single r in the denominator?

A

Because FORCE has r² in its denominator and work is force x distance so we get rid of one of the rs.

30
Q

What is the unit for electric potential?

A

JC⁻¹

Volts

31
Q

What is electric potential difference?

A

The difference in electric potential energy between two points.

The work done per unit charge to move a point charge between two points in an electric field.

32
Q

How do we calculate electric potential difference?

A

Calculate electric potential at both points and subtract them.

33
Q

What is the symbol for electric potential?

A

V

NOT UNIT

34
Q

What is the capacitance of an isolated sphere, radius R?

A

C = 4πε₀R

35
Q

What is an isolated sphere?

A

A sphere that is far away from other objects.

36
Q

What can an isolated sphere act as?

A

A capacitor.

37
Q

What is the difference between energy and electric potential regarding electric fields?

A

Energy is not per unit charge.

Potential is per unit charge.

Physics.Y1_Imported (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions